This invention relates in general to vehicle wheels and in particular to multi-piece wheels having a plurality of wheel discs.
It is known in the art to fabricate a vehicle wheel by attaching a wheel disc to a separately formed wheel rim. The wheel disc is typically cast or forged from a light weight metal, such as aluminum, titanium or magnesium, or an alloy of a light weight metal. The wheel disc can have a pleasing ornamental appearance with styled three dimensional contours. Additionally, casting or forging a disc is a simpler process than casting or forming an entire wheel. This is because the disc casting and corresponding mold are smaller than the casting and mold for an entire wheel.
The wheel rim is typically rolled; however, it also can be cast or forged. The wheel rim can be formed from the same metal or alloy as the wheel disc or from a metal which is different from the metal forming the wheel disc. A wheel having a rim and disc formed from two different metals is referred to a bimetal wheel. A common bimetal wheel includes a wheel rim rolled from a steel alloy attached to a wheel disc cast from a light weight metal alloy, such as an aluminum alloy. Rolling the wheel rim from steel provides strength, increased economy and flexibility. The wheel rim is permanently attached to the wheel disc by a conventional process, such as welding, brazing or soldering.
To further enhance the appearance of a bimetal wheel, it is known to extend the wheel disc in a radial direction to include the outboard tire retaining flange. Such a wheel disc is referred to as a full face wheel disc. The full face wheel disc is attached to a truncated outboard end of a partial wheel rim. The assembled full face wheel disc and partial wheel rim is called a full face wheel. When a tire is mounted upon a full face wheel, only the wheel disc is visible and the joint between the wheel disc and wheel rim is completely hidden. As a result, the wheel appears to be formed entirely from the wheel disc metal. The aesthetic appearance of the wheel is improved while the manufacturing and finishing processes are simplified.
Referring now to FIGS. 1 and 2, there is shown, generally at 10, a typical prior art bimetal full face wheel which is disclosed in U.S. Pat. No. 5,421,642 to Archibald. The wheel 10 includes a full face wheel disc 11 attached to the outboard end of a partial wheel rim 12. The wheel disc 11 is formed from a light weight metal or light weight metal alloy by a conventional process, such as gravity, low pressure or die casting, or forging. The wheel disc 11 includes a central wheel hub 13 which is supported by a plurality of wheel spokes 14 within an annular sidewall 15. An outboard tire retaining flange 16 extends in an outward radial direction from the sidewall 15. An outboard tire bead seat 16 is formed adjacent to the tire retaining flange 15. A cylindrical collar 17 which extends axially towards the inboard end of the wheel 10 is formed on the inboard surface of the sidewall 15. An annular weld anchor 18 is secured to the inboard surface of the wheel disc sidewall 15. The weld anchor is formed from a metal which is similar to the metal forming the wheel rim 12 to assure that a good weld is formed therebetween.
The wheel rim 12 is typically formed from steel strip stock with conventional rim roll forming machinery. Alternately, the wheel rim 12 can be cast or forged. The wheel rim 12 includes an outboard cylindrically shaped end 21 which forms an outboard tire bead seat 21. The wheel rim end 12 extends axially over the wheel disc collar 17. The wheel rim outboard end 21 also includes an outboard safety hump 23 and a deepwell wall 24. A deepwell 25 is formed in the wheel rim 12 adjacent to the deepwell wall 24. A leg portion 26 extends axially from the deepwell 25 toward an inboard end 27 of the wheel rim 12. An inboard safety hump 28 and inboard tire bead seat 29 are formed adjacent to the leg portion 26 on the inboard end 27 of the wheel rim 12. An inboard tire retaining flange 30 extends in an outward radial direction from the inboard wheel rim end 27.
The wheel rim 12 is secured to the wheel disc 11 by a continuous circumferential air-tight weld 35. The weld 35 is formed between the weld anchor 18 and the outboard end of the wheel rim 12 by a conventional welding process.